1. Field of the Invention
The present invention is directed, generally, to a filter element and, more particularly, to a filter element that removes harmful substances from air or smoke.
2. Description of the Invention Background
Over the years, substantial progress has been made in the United States in reducing the prevalence of cigarette smoking. Public awareness through advertising and the like has had a significant impact on encouraging those who would otherwise have started to smoke to not do so. For those who currently smoke, the broader availability and promotion of treatments for tobacco dependence, such as nicotine gum and patches, have provided methods that lead to smoking cessation. However, despite more than 30 years of progress in reducing the prevalence of smoking in the United States, approximately 48 million adult Americans, nearly one quarter of the adult population, continue to smoke.
Furthermore, it is estimated that roughly two billion people worldwide choose to smoke. Accordingly, societal health consequences and support for smoking prevention and cessation measures is clearly a global issue.
Most, if not all, physicians would agree that the most effective approach to reduce or eliminate the adverse health consequences associated with smoking is to stop, or never begin, smoking. From a practical standpoint, however, it is unlikely that smoking can be universally eliminated in the near term. Accordingly, even with the advances made in reducing the prevalence of smoking, the scope of tobacco dependence demands that physicians and scientists explore alternative treatment strategies that help reduce the harmful effects that impact those who choose to smoke.
A variety of strategies have been suggested to reduce the harmful effects of smoking. One common strategy is to construct a more effective filter element that removes the condensable gas phase components from the mainstream smoke prior to inhalation. One simple form of filter element is one that incorporates cellulose acetate tow and carbonaceous material, such as activated carbon, across its longitudinal length. In this form, carbonaceous material is typically spread over the cellulose acetate tow, with the tow acting as an adhesive to retain the carbonaceous material thereon. The tow is gathered and formed in a conventional manner, circumscribed by plug wrap, and cut into appropriate lengths to produce the filter element. The tow is longitudinally aligned in an end-to-end relationship with a tobacco rod and retained thereto using acircumscribing tipping material.
Some multi-sectional filter elements, such as dual-filter segment or triple-filter segment designs, are known to have advantages over single segment filter elements. In the multi-sectional filter element design, more than one segment may perform a separate component removal or airflow function to increase the overall filter effectiveness. For example, one known triple-filter configuration includes a tobacco rod end segment, a center filter segment, and a mouth end segment. The center segment includes a conventional carbonaceous filter material such as gathered carbon paper. The rod end and mouth end filter segments are formed of conventional material such as gathered cellulose acetate web. Passageways extending longitudinally through the filter element are said to direct the aerosol particles of the mainstream smoke through the filter element without physically interacting with the carbonaceous material, while the harmful gas phase components physically and chemically interact with the carbon paper for removal from the mainstream smoke.
As evidenced by the numerous filter element designs that have been proposed, the choice and amount of carbonaceous material and the arrangement of the segments of the multi-sectional filter element have a significant effect on the reduction of the gas phase components from the mainstream smoke. However, these designs may adversely impact the smoking experience by reducing the draw through the filter, or alter the chemical and physical properties of the aerosol particles therein. This latter effect causes the tobacco smoke to have an unpleasant dry or metallic flavor. Accordingly, many conventional filter elements provide only a modest reduction in gas phase components due to the choice of carbonaceous filter materials used therein, the arrangement of the filter segments, or the attempt to not adversely effect the smoking experience.
Despite efforts by those skilled in the art to improve filter elements, the conventional filter element designs have been unable to achieve reduction of gas phase components to near zero levels, without adversely effecting the smoking experience. Accordingly, a new filter element is needed that will satisfy these requirements.